A 380-12V, 1kW, 1MHz Converter Using a Miniaturized Split-Phase, Fractional Turn Planar Transformer

Ranjram, Mike K.; Perreault, David J.

doi:10.1109/tpel.2021.3103434

Cited by 32 publications

(7 citation statements)

References 29 publications

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“…The transformer power density is the ratio of output power to transformer volume. The loss percentage of the traditional fractional-turn transformers is 1.07% ~ 1.63% [11,12,14,15,17], while that of the proposed transformer is only 0.62%, which is reduced by 42% ~ 62%. The power density of the traditional fractional-turn transformers is 39.5W/cm 3 ~ 72.7W/cm 3 [11,12,14,15,17], while that of the proposed transformer is as high as 140.9W/cm 3 , which is increased by 94% ~ 260%.…”

Section: Vexperimental Resultsmentioning

confidence: 90%

“…This structure is used for the first time in the application with a wide voltage range, and the equivalent transformer ratio can be changed by configure the rectifier bridge [13]. Further, 1MHz LLC DCX is built based on the fractional-winding structure and achieves a full-load efficiency of 96.8% [14]. In [15], a 750kHz, 600W half-turn structure LLC DCX was developed where Litz wire is used for the primary winding and PCB trace is used for the secondary winding.…”

Section: Introductionmentioning

confidence: 99%

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Integrated Fractional-Turn Planar Transformer for MHz and High-Current Applications

Wang

Gao

Guo

et al. 2023

IEEE Trans. Power Electron.

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In MHz and high current applications, planar transformers face problems such as significant winding loss and limited winding current-carrying capacity, which seriously restrict converter's efficiency and power density improvement. This paper proposes a fractional-turn planar transformer structure and embeds key power devices into the transformer. The proposed method can significantly shorten the winding length, thus reducing winding losses. At the same time, the high integration of the transformer and key power devices can effectively reduce the overall volume of the converter and eliminate terminal losses. The analysis and optimization of the proposed integrated fractional-turn transformer are presented in detail. Finally, a 380V-12V 1kW unregulated LLC is built with the proposed integrated transformer. The full-load efficiency is 97.7%, and the power density is 99W/cm 3 , both of which are the highest among the state-of-the-art prototypes with similar specifications. 1

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Section: Vexperimental Resultsmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Integrated Fractional-Turn Planar Transformer for MHz and High-Current Applications

Wang

Gao

Guo

et al. 2023

IEEE Trans. Power Electron.

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“…However, although the side legs help extend the direction of the magnetic flux, the magnetic reluctances of the side legs will be slightly larger than those of the middle magnetic plates so that the magnetic flux distribution is uneven, and the core utilization is reduced. Therefore, Ranjram et al [17] proposed an integrated scheme with the air gap on the magnetic plates and the side legs, which made the magnetic density distribution more uniform, but increased the number of magnets. It also led to higher costs and fixing problems.…”

Section: Structural Design Of Planar Magnetic Coresmentioning

confidence: 99%

Overview of Planar Magnetics for High-frequency Resonant Converters

Liu

Song

et al. 2022

Chin. J. Electr. Eng.

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With the continuous development of power supplies toward miniaturization, light weights, and high levels of integration, research on high-frequency resonant conversion based on planar magnetics is becoming extensive. Combining the soft-switching characteristics of resonant converters with those of wide bandgap devices, the switching frequency can be increase to the MHz range, and the power density of the entire system can be improved considerably. However, higher switching frequencies impose new requirements for the structural design, loss distribution, and common mode (CM) noise suppression of passive magnetic components.Herein, a thorough survey of the-state-of-the-art of planar magnetics in high-frequency resonant converters is conducted. Printed circuit board winding-based planar magnetics, magnetic integration, and power-loss optimization strategies are summarized in detail.Suppression methods for CM noise in high-frequency planar magnetics are also clarified and discussed. An insight view into the future development of planar magnetics for high-frequency resonant converters is presented.

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“…To address the matter, several techniques such as matrix transformers, integrated magnetics, fractional turn, flux cancellation, interleaved windings, single and multiphase circuits have been proposed and tested at MHz switching frequency. Numerous studies showed that the power density and the efficiency has improved because of increasing the switching frequency to MHz range [2][3][4][5]. Certainly, the overall power density and efficiency of the converter has increased.…”

Section: Introductionmentioning

confidence: 99%

“…1 and Fig. 2) [2][3][4][5]. As an example, the box volume and the net volume of the magnetics designed in [2] are 14.73 cm 3 and 10.88 cm 3 .…”

Section: Introductionmentioning

confidence: 99%

High Performance Planar Magnetics Based on an Unbalanced-Flux Approach

Barg

Barg²,

Bertilsson

2023

IEEE Open J. Power Electron.

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this paper presents a new design concept to increase the efficiency and the power density of planar magnetics. In contrast to the existing magnetics, which are built using the balanced magnetic flux density design, the proposed design concept generates unbalanced magnetic flux density across the different parts of the magnetic core. The theoretical analysis shows that the core loss of the unbalanced-flux design can be reduced by more than 50% compared to the existing one. The core loss reduction brings several benefits to planar magnetics such as: high power capability, better thermal performance and wider safe operating area (SOA). The proposed design is experimentally evaluated and compared with the balanced-flux design. The experimental results are in good consistency with its theoretical counterparts. The measured core loss are decreased by more than 50% and the power density is increased by more than 250%.

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A 380-12V, 1kW, 1MHz Converter Using a Miniaturized Split-Phase, Fractional Turn Planar Transformer

Cited by 32 publications

References 29 publications

Integrated Fractional-Turn Planar Transformer for MHz and High-Current Applications

Integrated Fractional-Turn Planar Transformer for MHz and High-Current Applications

Overview of Planar Magnetics for High-frequency Resonant Converters

High Performance Planar Magnetics Based on an Unbalanced-Flux Approach

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